The present invention relates to machines for forming the flanges of metal workpieces and, more particularly, the corners of such flanges.
As is well known, brake presses and the like are utilized to bend sheet metal to provide flanges extending about only a portion of the periphery of a panel or about the entire periphery as may be desired. Some panel forming operations notch a portion of the blank at the corners to facilitate bending and avoid crenulated or serpentine corners. However, a closed corner in the panel may then only be facilitated by subsequent welding.
To provide closed, straight corners for unbroken flanges from solid material without welding, flange corner forming machines have been developed which smooth or flatten the crenulated corner areas produced in a brake press forming of the flange. Illustrative of such machines are German Patent AS 40 09 466 and U.S. Pat. No. 6,047,585. A workpiece which has been formed with crenulated corners is placed within such a machine and the corner areas are profiled to provide a substantially vertical flange corner. These machines use the combination of a forming roll and a die upon which the workpiece is supported. As the forming roll is moved along the corner flange of the workpiece, it forces the metal of the flange against the surface of the die and forms the metal of the flange adjacent the corner. Subsequently, the workpiece is generally transferred to a shear wherein excess metal at the corners of the flange is removed.
Although such machines have proven useful in the forming of flange corners on metal workpieces, the height of the flange which can be effectively processed is limited and it will often vary with the metal composition and thickness.
It is an object of the present invention to provide a novel flange corner forming machine which enables the formation of flange corners of greater height to material thickness ratio for a given material than are presently obtainable.
It is also an object to provide such a flange corner forming machine which is rugged in construction and efficient in its operation.
A further object is to provide such a flange corner forming machine in which the tooling can be readily interchanged for workpieces of different metal composition and thickness, and for flanges of different heights.
A still further object is to provide a novel method for forming sheet metal flanges to provide smooth vertical corners with solid material integrity and without the requirement of welding.